<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>

    .file {
      display: none;
    }

    .custom-file-button {
      width:15px;
      height:15px;
      line-height: 15px;
      display: inline-block;
      padding: 10px 20px;
      background-color: #81AA0A;
      color: #333;
      border: 1px solid #999;
      cursor: pointer;
      border-radius:0 15px 15px 0 ;
    }

    .custom-file-button:hover {
      background-color: #ccc;
    }

  </style>
</head>
<body>
  <div>
    <label for="file" class="custom-file-button">+</label>
    <input type="file" id="file" class="file" name="file" />

  </div>
</body>
</html>
